I have a 04' sierra 2500 6.0, and today i just noticed this for the first time. When in park only, i press the brake petal down it will make a click sound that comes from the dash, and it will click again when i let off, but only in park. It has never done that before. I was curious if anyone else had had that happen to them, if it was normal, or a serious problem. What it sounds like to me is a cable releasing or something. Thankyou.

bluesierra51

 

shift/brake interlock......won't allow you to pull out of park unless the brake is pressed